1. Field of the Invention
The present invention relates to a telescopic tube, and more particularly to a telescopic tube having an outer tube, an inner tube movably received in the outer tube and a handle pivotally connected to the inner tube to control activation of a clamping mechanism applied to a notched post in the outer tube such that relative position between the inner tube and the outer tube is changeable.
2. Description of Related Art
A telescopic tube mechanism normally is applied to a stand and aimed to adjust the height of the stand to match the height of the user. A conventional telescopic tube mechanism has a first tube and a second tube. A connector is provided between the first tube and the second tube. When adjustment of the height of the telescopic tube is required, the operator first unscrews the connector to release the engagement between the first tube and the second tube. Then the operator extends or retracts the second tube relative to the first tube. After the height of the telescopic tube is changed, the operator screws the connector to secure the relative position between the first tube and the second tube.
The entire process of unscrewing and screwing the connector to change the height of the telescopic tube is quite troublesome. U.S. Pat. No. 4,671,479 discloses an inventive telescopic tube mechanism having an outer tube and an inner tube movably received in the outer tube. A handle is provided on a top portion of the inner tube to activate a spring so that a conical head of an inner sleeve received in the inner tube is able to be released from limit of the outer tube. When the inner sleeve is released, pulling the inner tube is possible to change the relative position between the inner tube and the outer tube. However, because the limit of the outer tube to the inner sleeve is based on the friction between the inner surface of the outer tube and the inner sleeve, after a long period of time changing the relative position between the inner tube and the outer tube, the grip to the inner sleeve is worn and thus positioning effect between the inner tube and the outer tube is diminished. Furthermore, rotation between the inner tube and the outer tube happens, which is quite annoying to the operator.
To overcome the shortcomings, the present invention tends to provide an improved telescopic mechanism to mitigate and obviate the aforementioned problems.
The primary objective of the present invention is to provide an improved telescopic tube of which the height of the tube can be changed easily by operating a handle pivotally engaged with a seat.
Another objective of the present invention is to provide an improved securing device inside the telescopic tube such that when the handle is operated, a pair of clamping claws of the securing device is able to release a notched post inside the outer tube so that the height of the telescopic tube can be changed.